Analysis of Bottom Sediment to Estimate 

Nonpoint-Source Phosphorus Loads for 

1981-96 in Hillsdale Lake, Northeast 

Kansas

By KYLE E. JURACEK

U.S. GEOLOGICAL SURVEY 

Water-Resources Investigations Report 97-4235

Prepared in cooperation with the

JOHNSON COUNTY ENVIRONMENTAL DEPARTMENT and 

JOHNSON COUNTY UNIFIED WASTEWATER DISTRICTS

Lawrence, Kansas 

1997
U.S. DEPARTMENT OF THE INTERIOR 

BRUCE BABBITT, Secretary

U.S. GEOLOGICAL SURVEY 

MARK SCHAEFER, Acting Director

The use of firm, trade, and brand names in this report is for identification purposes 

only and does not constitute endorsement by the U.S. Geological Survey.

For additional information write to:

District Chief 

U.S. Geological Survey 

4821 Quail Crest Place 

Lawrence, Kansas 66049-3839

Copies of this report can be purchased 

from:

U.S. Geological Survey 

Information Services 

Box 25286 

Federal Center 

Denver, CO 80225-0826
CONTENTS

Abstract.................................................................................................................................................................^ 1

Introduction..............................................................................................~^ 1

Description of Hillsdale Lake Basin............................................................................................................................ 4

Acknowledgments....................................................................................................................................................... 4

Methodology................................................................................................................................................................^ 4

Sediment-Core Collection and Analysis...................................................................................................................... 4

Bathymetric Surveys.................................................................................................................................................... 7

Estimation of Bottom-Sediment Thickness, Volume, and Mass ................................................................................. 7

Estimation of Phosphorus Loads................................................................................................................................. 8

Sediment Deposition in Hillsdale Lake................................................................................................................................. 9

Phosphorus in Hillsdale Lake................................................................................................................................................ 15

Estimated Annual Phosphorus Loads from Nonpoint Sources.............................................................................................. 22

Summary........................................................................................................._^ 23

References...................................................................^ 23

Supplemental Information..................................................................................................................................................... 25

FIGURES

1-3. Maps showing:

1. Location of Hillsdale Lake Basin in northeast Kansas and point sources of phosphorus discharge within

the basin ............................................................................................................................................................. 2

2. Location of sediment-coring sites, bathymetric range lines, and boundaries of out-of-channel lake

partitions at Hillsdale Lake ................................................................................................................................ 5

3. Estimated bottom-sediment thickness in Hillsdale Lake, 1996......................................................................... 10

4. Graph showing estimated bottom-sediment thickness in the Big Bull Creek channel of Hillsdale Lake, 1996........ 11

5. Graph showing estimated bottom-sediment thickness in the Little Bull Creek channel of Hillsdale Lake, 1996..... 12

6. Map showing estimated bulk density of bottom sediment in Hillsdale Lake, 1996................................................... 16

7. Map showing total phosphorus concentrations in bottom sediment of Hillsdale Lake, 1996.................................... 19

8-13. Graphs showing comparison of 1996 U.S. Geological Survey bathymetric data, 1978 U.S. Army Corps of

Engineers topographic data, and 1993 and 1996 U.S. Army Corps of Engineers bathymetric data for Hillsdale Lake:

8. Range line 6................................................................................................................................................ 28

9. Range line 5.................................................................^ 29

10. Range line 4........................................................................................................................................................ 30

11. Range line 15...................................................................................................................................................... 31

12. Range line 13.................................................................. 32

13. Range line 2................................................................ 33

14-23. Graphs showing comparison of 1978 U.S. Army Corps of Engineers topographic data and 1996 U.S. Army 

Corps of Engineers bathymetric data for Hillsdale Lake:

14. Range line !..........................................................................................................._ 34

15. Range line 3........................................................................................................................................................ 35

16. Range line 7........................................................................................................................................................ 36

17. Range line 8......................................................................................................................................................^ 37

18. Range line 9.....................................................................................................»^ 38

19. Range line 10...............................................................^ 39

20. Range line 12........................................................................................................_^ 40

21. Range line 14.................................................................. 41

22. Range line 16...................................................................................................................................................... 42

23. Range line 18................................................................... 43

Contents III
FIGURES Continued

24. Map showing additional bathymetric survey lines completed by the U.S. Geological Survey at Hillsdale Lake in

1996.................................................................................,_^^ 44

25-34. Graphs showing 1996 U.S. Geological Survey bathymetric data for Hillsdale Lake:

25. Range line 19 .............................................................................................. 45

26. Range line 20....................................................................................,..._^ 46

27. Range line 21.................................................................................................._^ 47

28. Range line 22...................................................................................................._^ 48

29. Range line 23 ............................................................. 49

30. Range line 24...................................................................^^ 50

31. Range line 25 ............................................................_ 51

32. Range line 26..................................................................................................................................................^^ 52

33. Range line 27 ............................................................. 53

34. Range line 28........................................................................................._^ 54

35. Graph showing relation of sediment bulk density to percent moisture content for 19 sediment-core samples

from Hillsdale Lake.................................................................................................................................................... 55

TABLES

1. In-channel bottom-sediment thickness estimated from 1996 bathymetry and 1978 topographic information

at bathymetric range-line sites in Hillsdale Lake.................................................................................................... 9

2. Estimated length, mean width, mean bottom-sediment thickness, and bottom-sediment volume in

submerged stream-channel segments in Hillsdale Lake, 1996............................................................................... 13

3. Bottom-sediment thickness measured in core samples collected at out-of-channel sites in Hillsdale Lake, 1996 14

4. Estimated area, mean bottom-sediment thickness, and bottom-sediment volume in out-of-channel lake

partitions of Hillsdale Lake, 1996........................................................................................................................... 14

5. Estimated bottom-sediment volume for Hillsdale Lake, 1996 ............................................................................... 14

6. Estimated bulk density of bottom sediment at in-channel sites in Hillsdale Lake, 1996 ...................................... 15

7. Estimated bulk density of bottom sediment at out-of-channel sites in Hillsdale Lake, 1996................................ 15

8. Estimated bottom-sediment volume, mean bulk density, and mass in submerged channels of Hillsdale Lake,

1996............................................................................................................................................^ 17

9. Estimated bottom-sediment volume, mean bulk density, and mass in out-of-channel lake partitions of

Hillsdale Lake, 1996.............................................................................................._^ 18

10. Estimated bottom-sediment mass in Hillsdale Lake, 1996..................................................................................... 18

11. Total phosphorus concentrations and percent moisture content of bottom sediment at in-channel sites in

Hillsdale Lake, 1996............................................................................................................................................... 20

12. Total phosphorus concentrations and percent moisture content of bottom sediment at out-of-channel sites in

Hillsdale Lake, 1996.............................................................................................^^ 22

13. Latitude and longitude coordinates for the end points of the U.S. Army Corps of Engineers range lines used in

the bathymetric surveys of Hillsdale Lake.............................................................................................................. 27

IV Analysis of Bottom Sediment to Estimate Nonpoint-Source Phosphorus Loads for 1981-96 in Hillsdale Lake, Northeast Kansas
CONVERSION FACTORS, ABBREVIATIONS, AND VERTICAL 

DATUM

Multiply

acre

acre

acre

acre

acre-foot (acre-ft)

acre-foot (acre-ft)

cubic foot (ft3)

cubic foot (ft3)

cubic foot per second (ft3/s)

cubic meter (m3)

foot (ft)

gram(g)

inch (in.)

kilogram (kg)

kilogram per cubic meter (kg/m3)

meter (m)

mile (mi)

milligram per liter (mg/L)

milligram per kilogram (mg/kg)

pound (Ib)

pound per cubic foot (lb/ft3)

square foot (ft2)

square mile (mi2)

square mile (mi2)

By

0.40468

43,560

4,047

0.001562

43,560

1,233

0.02832

28.32

0.02832

35.31

0.3048

0.03527

2.54

2.205

0.06243

3.281

1.609

1.0

1.0

0.45351

16.02

0.09290

259.0

2.590

To obtain

hectare

square foot

square meter

square mile

cubic feet

cubic meter

cubic meter

liter

cubic meter per second

cubic foot

meter

ounce

centimeter

pound

pound per cubic foot

foot

kilometer

part per million

part per million

kilogram

kilogram per cubic meter

square meter

hectare

square kilometer

Temperature can be converted to degrees Celsius (°C) or degrees Fahrenheit (?F) by 

the equations:

°C = 5/9 (°F - 32)

°F = 9/5 (°C) + 32.

Sea level: In this report, "sea level" refers to the National Geodetic Vertical Datum of 

1929 a geodetic datum derived from a general adjustment of the first-order level nets of the 

United States and Canada, formerly called Sea Level Datum of 1929.

Contents
VI Analysis of Bottom Sediment to Estimate Nonpoint-Source Phosphorus Loads for 1981-96 in Hillsdale Lake, Northeast Kansas
Analysis of Bottom Sediment to Estimate NonpointSource Phosphorus Loads for 1981-96 in Hillsdale 

Lake, Northeast Kansas

By Kyle E. Juracek

Abstract

Bottom sediment in Hillsdale Lake, northeast Kansas, was analyzed as a means of estimating the annual load of total phosphorus deposited 

in the lake from nonpoint sources. Topographic, 

bathymetric, and sediment-core data were used to 

estimate the total mass of phosphorus in the 

lake-bottom sediment. Available streamflow and 

water-quality data were used to compute the mean 

annual mass of phosphorus (dissolved plus suspended) exiting the lake as well as the mean 

annual load of phosphorus added to the lake from 

point sources. A simple mass balance then was 

used to compute the mean annual load of phosphorus from nonpoint sources.

Mean annual sediment deposition from 

1981 through 1996 was estimated to be 265 million pounds (120 million kilograms). The total 

mass of phosphorus in the lake-bottom sediment 

was estimated to be 924,000 kilograms, with a 

mean annual load of 62,000 kilograms. The mean 

annual mass of phosphorus exiting in the lake outflow was estimated to be about 8,000 kilograms. 

The mean annual loads of phosphorus added to the 

lake from point and nonpoint sources were estimated to be 5,000 and 65,000 kilograms, respectively. Thus, the contribution to the total mean 

annual phosphorus load in Hillsdale Lake from 

point sources is about 7 percent and from nonpoint 

sources, about 93 percent.

INTRODUCTION

Hillsdale Lake is a Federal impoundment on Big 

Bull Creek in northwest Miami County, northeast 

Kansas (fig. 1). Completed in 1981, the lake is used for 

flood control, water supply, fish and wildlife habitat, 

and recreation. With the rapid expansion of urbanization in southern Johnson County, the use of the lake as 

a water-supply source is expected to increase substantially. As early as 1985, concerns existed that water 

quality in Hillsdale Lake may be affected by urbanization and increased point- and nonpoint-source discharges of phosphorus within the basin. Hillsdale Lake 

is reportedly the third-most, point-source-affected Federal lake in Kansas (Carney, 1994).

Phosphorus is an important nutrient because it is 

the principal limiting factor for primary production in 

most freshwater environments (Hakanson and Jansson, 

1983). If phosphorus concentrations are too large, algal 

growth may become excessive and cause taste and odor 

problems for water suppliers. Additionally, excessive 

algal growth may be detrimental to aquatic life in, as 

well as discourage recreational use of, the lake. On the 

basis of widely accepted chlorophyll-a criteria, Hillsdale Lake has been classified as eutrophic by the Kansas Department of Health and Environment (KDHE) 

(Carney, 1994). A eutrophic lake contains nutrient-rich 

water and supports high biotic productivity (Cole, 

1983).

Sediment deposition in a lake is important because 

about 95 percent of the phosphorus in streams tends to 

adhere to sediment particles (Hem, 1985). The sediment transported by streams and deposited in a lake 

acts as a sink where phosphorus may be stored and as a 

source of phosphorus to the overlying water and biota 

(Baudo and others, 1990). Although the release of

Introduction 1
95°05' 95'

38°5D' 

Johnson County 

New Century 

AirCenter

38°4D' 

Base from Kansas Geological Survey digital data, 1:24,000,1991

and U.S. Geological Survey digital data, 1:100,000,1983 

Lambert Conformal Conic projection 

Standard parallels 33° and 45°, central meridian 98°15'

0 1 3 MILES

_l______[_

0 1 2 3 KILOMETERS

EXPLANATION

I F T'TTTT f~~i~~t~1~~!"t~[

j-Y-rV-TK A N '

I ' I I I I r

Johnson 

County 

Miami 

County

Area of 

enlargement

Extent of Hillsdaie Lake at conservation-pool 

elevation (917 feet above sea level)

Boundary of Hillsdaie Lake Basin 

Point source of phosphorus discharge

Index map

Figure 1. Location of Hillsdaie Lake Basin in northeast Kansas and point sources of phosphorus discharge within the 

basin.

2 Analysis of Bottom Sediment to Estimate Nonpoint-Source Phosphorus Loads for 1981-96 in Hillsdaie Lake, Northeast Kansas
phosphorus from lake-bottom sediment may occur 

under aerobic or anoxic conditions, the release rate is 

typically much greater during anoxic conditions (Bostrom and others, 1982; Wetzel, 1983). However, Welch 

and Cooke (1995) state that several mechanisms can 

combine to produce relatively high phosphorus release 

rates in shallow, aerobic lakes. Hillsdale Lake is typified by aerobic conditions with water depths ranging 

from shallow to relatively deep (50 ft or more).

Aside from resuspension, the release of phosphorus from lake-bottom sediment involves a mobilization 

from particulate to dissolved form followed by transport into the water column. Important environmental 

factors in the mobilization of phosphorus include redox 

potential, pH, and temperature. Transport processes 

include diffusion, turbulence, and bioturbation (Hakanson and Jansson, 1983).

In 1991, the Hillsdale Water-Quality Protection 

Project was initiated by the Hillsdale Lake Region 

Resource Conservation and Development Council 

(RC&D) to establish long-term protection of the lake 

and drainage area. The goal of the project is to implement a nonpoint-source pollution-control program to 

manage further nutrient enrichment of Hillsdale Lake. 

Specifically, the objectives are to maintain a mean 

annual total phosphorus concentration of 0.06 mg/L or 

less in Hillsdale Lake water and a mean annual total 

phosphorus concentration of 0.10 mg/L, a low-flow 

mean concentration of 0.05 mg/L, and a runoff mean 

concentration of 0.40 mg/L in lake tributary water. 

RC&D began water-quality sampling of the streams 

flowing into Hillsdale Lake in 1993. The sampling was 

performed during storm-runoff and base-flow 

conditions.

In a recent study, the U.S. Geological Survey 

(USGS) focused on determining both point and nonpoint sources of phosphorus during low-flow conditions (Putnam, 1997). Results of the study indicate that 

the point sources in the Hillsdale Lake Basin (fig. 1) are 

significant contributors to the phosphorus loads in Big 

Bull Creek and Little Bull Creek during low-flow conditions. The mean concentrations of total phosphorus 

ranged from 0.05 to 4.9 mg/L in water from 44 sites 

sampled in the Hillsdale Basin during low-flow conditions from May 1994 through May 1995. Because concentrations in water from these sites equaled or 

exceeded the RC&D proposed low-flow total phosphorus concentration of 0.05 mg/L, it was concluded that 

nonpoint-source contamination is significant during

low-flow conditions in the areas of the basin with no 

point-source discharges (Putnam, 1997).

Several studies have provided estimates of annual 

point- and nonpoint-source loads of phosphorus to 

Hillsdale Lake. Montgomery (1991) used a modeling 

approach and the limited water-quality data available 

to estimate a mean annual phosphorus load of about 

24,000 kg, with respective contributions from point 

and nonpoint sources of 20 and 80 percent. Carney 

(1994) also used a modeling approach and the limited 

water-quality data available to estimate a mean annual 

phosphorus load of about 19,000 kg, with respective 

contributions from point and nonpoint sources of 26 

and 74 percent. Carney's study also indicated the need 

for a reduction of annual phosphorus loads from both 

point and nonpoint sources by 28 to 45 percent (Carney, 1994). Using water-quality data collected in 1994, 

a study by the Johnson County Environmental Department (JCED) and the RC&D estimated the annual total 

phosphorus load contributed to Hillsdale Lake to be 

about 65,000 kg, of which 92 percent was from nonpoint sources (Holt, 1996). Because of the limited historical water-quality data available and the large 

hydrologic variability over time, an alternative 

approach was needed to determine the annual phosphorus loads to Hillsdale Lake from point and nonpoint 

sources.

A 2-year study by USGS, in cooperation with 

JCED and the Johnson County Unified Wastewater 

Districts, was begun in 1996 to estimate the historical 

phosphorus loads to the lake as well as the historical 

contributions of point and nonpoint sources. The historical perspective is important because regulatory and 

remediation strategies may be different depending on 

the total and relative contributions of phosphorus from 

the various point and nonpoint sources within the Hillsdale Lake Basin. The specific study objectives were to:

1. estimate the volume and mass of bottom sediment in 

the lake as well as the mean annual deposition 

since closure of Hillsdale Dam in 1981;

2. estimate the total mass of phosphorus in the

lake-bottom sediment as well as the mean annual 

load; and

3. estimate the historical mean annual phosphorus 

loads to the lake from nonpoint sources. 

The purpose of this report is to present the results 

of the USGS study to estimate the historical loads of 

phosphorus from nonpoint sources to Hillsdale Lake. 

From a national perspective, the methods and results 

presented in this report provide guidance and perspecIntroduction
live for future lake studies concerned with the issues of 

sedimentation and water quality.

Description of Hillsdale Lake Basin

The Hillsdale Lake Basin is a 144-mi2 area in Douglas, Franklin, Johnson, and Miami Counties, northeast 

Kansas. The lake has a surface area of 4,580 acres and 

a water-storage capacity of 68,000 acre-ft at the conservation-pool elevation of 917 ft above sea level. Water 

storage in Hillsdale Lake began on September 19, 

1981, and the lake reached conservation-pool elevation 

on February 23,1985. Principal tributaries that contribute flow directly to Hillsdale Lake include Big Bull 

Creek, Little Bull Creek, Rock Creek, Wade Branch, 

and Scott Branch (fig. 1). Bedrock in the basin is 

mostly Pennsylvanian-age limestone and shale. The 

predominate land use in the basin is agriculture, with 

about 40 percent of the land used for cultivated crops 

(Putnam, 1997). About 20 percent of the basin is 

wooded (Carney, 1994). Land use in the remainder of 

the basin is dominated by additional agricultural uses 

(for example, feedlots and pasture) as well as urban and 

residential uses.

Several point sources of phosphorus discharge are 

located within the Hillsdale Lake Basin and include 

wastewater-treatment facilities at Gardner, Edgerton, 

and the Johnson County New Century AirCenter and 

wastewater lagoons at Connestoga Mobile Home Park 

and Lone Elm Estates (Carney, 1994) (fig. 1). Nonpoint 

sources of phosphorus in the Hillsdale Lake Basin 

include soils, bedrock, septic systems, feedlots, and 

cropland.

Long-term (1961-90) mean annual precipitation, 

as computed for Paola, Kansas, located 5 mi south of 

Hillsdale Lake, is 40.8 in. About 76 percent of the 

annual precipitation is received during the growing 

season (April through October) (National Oceanic and 

Atmospheric Administration, 1993).

Acknowledgments

The author gratefully acknowledges the waterquality information provided by JCED and KDHE and 

the water-quality, sediment, topographic, and bathymetric information provided by the U.S. Army Corps 

of Engineers (COE).

METHODOLOGY

The objectives of this study were accomplished 

using available as well as newly collected information. 

Available information included COE data on total 

phosphorus concentrations in the lake outflow, JCED 

and KDHE data on annual phosphorus loads from the 

five largest point sources in the basin, COE 1978 

topographic survey information for the lake (preimpoundment), COE 1993 and 1996 bathymetric information for the lake, USGS discharge data for the lake 

outflow, and USGS l:24,000-scale topographic quadrangles that were used as base maps for the study. New 

information was obtained through lake-bottom sediment coring and additional bathymetric surveying.

Sediment-Core Collection and Analysis

Bottom-sediment cores were collected during the 

summer and fall of 1996 at 53 sites (fig. 2) within the 

lake using a gravity corer. The liner used in the corer 

was cellulose acetate butyrate transparent tubing with a 

2.875-in. outside diameter and a 2.625-in. inside diameter. The coring sites were located to provide a spatially 

representative sample of lake-bottom sediment both in 

and outside of submerged stream channels. A total of 

22 in-channel and 31 out-of-channel sites were cored. 

Several of the cores were collected on or near the range 

lines used in the bathymetric surveys (fig. 2). The latitude and longitude for each coring site was obtained 

using global-positioning-system (GPS) technology 

with a horizontal accuracy ranging from 15.1 to 32.8 ft 

and a mean horizontal accuracy of 22.3 ft.

The sediment cores were refrigerated and typically 

processed within 48 hours of collection at the USGS 

laboratory in Lawrence, Kansas. Initially, each core 

was extracted from the liner and placed in a tray. Maintained at a slight incline to preserve the vertical integrity of the sediment, the core was split longitudinally 

(that is, lengthwise) to expose the relatively undisturbed inner part of the core for examination and sampling. On the basis of differences in moisture content, 

texture, and organic matter content (for example, root 

hairs, sticks, seed pods, leaves), the boundary between 

the lake-bottom sediment and the underlying 

pre-impoundment land-surface (or channel-bed) material was determined. The lake-bottom sediment was 

characterized by higher moisture content, finer texture,

4 Analysis of Bottom Sediment to Estimate Nonpoint-Source Phosphorus Loads for 1981-96 in Hillsdale Lake, Northeast Kansas
95°01' 

38°45'

591 57' 55' 53' 94°51'

43'

41'

38°39' Hillsdale 

Dam

SC-3

Base from U.S. Geological Survey digital data, 1:24.000,1973

Lambert Conformal Conic projection

Standard parallels 33° and 45°, central meridian 98°15'

CD

1

3 MILES

B

n1

EXPLANATION

Extent of Hillsdale Lake at conservation-pool 

elevation (917 feet above sea level)

Bathymetric range line and numbei Established by 

U.S. Army Corps of Engineers

Boundary for out-of-channel lake partitions and 

partition identifiers

In-channel sediment-coring site and number 

Out-of-channel sediment-coring site and number 

Bathymetric range-line site and number

3 KILOMETERS

Figure 2. Location of sediment-coring sites, bathymetric range lines, and boundaries of out-of-channel lake partitions at 

Hillsdale Lake.

Methodology 5
and little if any visible organic matter as compared to 

the underlying material. The thickness of the lake-bottom sediment in each core was measured to the nearest 

0.01 ft.

The number of samples extracted from each core 

was dependent on the thickness of the lake-bottom sediment. Typically, a minimum of 0.2 ft of sediment was 

required for sample processing. Cores collected at the 

submerged in-channel coring sites typically had sediment thicknesses of several feet. For these in-channel 

cores, there was sufficient sediment for the extraction 

of five samples to assess the distribution of phosphorus 

concentrations with depth. Cores collected at the 

out-of-channel sites typically had sediment thicknesses 

of less than 0.5 ft. For these out-of-channel cores, 

either one or two samples were extracted depending on 

the sediment thickness. Each core was divided into segments of equal length. Then, an equal volume of sediment (defined as the space occupied by the sediment 

particles, water, and gases as measured in cubic units) 

was extracted longitudinally from both halves of each 

segment and combined.

The combined sediment volume was homogenized 

and quartered into subsamples of at least 10 g each. 

Two of the subsamples were placed in separate sample 

bottles, labeled, and refrigerated for subsequent phosphorus analysis. One subsample was analyzed for percent moisture content. This subsample was weighed to 

the nearest 0.10 g, oven dried at about 45 °C for 48 

hours, and reweighed. Oven drying of the subsample 

continued as it was reweighed on a daily basis until no 

additional moisture loss was observed. The percent 

moisture content then was computed as follows:

ED = mlv, (2)

M=[(w-m)/w](100), (1)

where M is the percent moisture content,

w is the wet weight of the sample (in grams),

and 

m is the mass (dry weight) of the sample (in

grams).

Analyses of sediment samples for percent moisture 

content were performed at the USGS laboratory in 

Lawrence, Kansas.

Sediment density as bulk density also was estimated for most of the in-channel cores as well as a few 

out-of-channel cores for which sufficient sediment volume was available. Bulk density was computed as 

follows:

where BD is the bulk density (in kilograms per cubic

meter), 

m is the mass (dry weight) of the sample (in

kilograms), and 

v is the volume of the sample (in cubic

meters).

The volume for a cylindrical core sample was computed as:

v = h(nd2!4\ (3)

where v is the volume of the sample (in cubic

meters), 

h is the height of the cylinder (in meters),

and 

d is the diameter of the cylinder (in meters)

(Gordon and others, 1992).

The bulk densities then were converted to pounds per 

cubic foot for use in subsequent computations. Analyses of sediment samples for bulk density were performed at the USGS laboratory in Lawrence, Kansas. 

For the in-channel cores that were divided into five 

segments of equal length, the second and fourth segments were sampled for bulk-density analysis. The two 

results then were averaged to estimate a representative 

bulk density for the site. For the out-of-channel cores, 

the limited amount of bottom sediment dictated that a 

single segment, either the middle half or the entire 

thickness of the core, be sampled. For each segment, 

one-half of the sediment volume, split longitudinally, 

was extracted for bulk-density analysis. The other half 

of the segment was required for phosphorus analysis. 

The bulk-density samples then were weighed, oven 

dried, and reweighed as previously described to estimate the mass of the samples.

Analyses of bottom-sediment samples for total 

phosphorus concentration were performed at the USGS 

National Water-Quality Laboratory in Arvada, Colorado, using the method described by Fishman and 

Friedman (1989). In this report, results are reported as 

mass (dry weight) of total phosphorus. As part of the 

study, 27 quality-assurance samples in the form of 

duplicate samples were analyzed. A total of 140 analyses were performed. Data for all bottom-sediment samples analyzed for total phosphorus are stored in the 

USGS WATSTORE data storage and retrieval system 

and the U.S. Environmental Protection Agency's 

STORET system.

6 Analysis of Bottom Sediment to Estimate Nonpoint-Source Phosphorus Loads for 1981-96 in Hillsdale Lake, Northeast Kansas
Bathymetric Surveys

Bathymetric surveys were performed independently by USGS and COE during the summer of 1996 

using GPS technology to record the geographic location of the boat on the lake and a fathometer system to 

determine the depth to the sediment/water interface. 

The GPS and fathometer data were recorded digitally 

using a data-logging unit. The bathymetric surveys 

were conducted along 16 range lines that were 

established by the COE in 1978 (fig. 2; see also 

figs. 8-23 in the "Supplemental Information" section at 

the end of this report). USGS collected additional 

bathymetric data along lines running between and 

across the 16 COE range lines (see figs. 24-34 in the 

"Supplemental Information" section). The additional 

bathymetric data were not used for the estimates provided in this report as there were no preceding data to 

provide a basis for comparison. However, the additional bathymetric data may provide supplemental 

baseline data for future studies of Hillsdale Lake. The 

latitude and longitude coordinates for the end points of 

COE range lines used in this study are provided in table 

13 in the "Supplemental Information" section. The reliability of the fathometer was verified twice each day by 

suspending a metal pipe at known depths directly 

below the transducer. The accuracy of both USGS and 

COE bathymetric data is ± 0.25 ft (Steve Sando, U.S. 

Geological Survey, oral commun., 1996; Harry 

Hart well, U.S. Army Corps of Engineers, oral commun., 1997). A graphic comparison of the 1996 USGS 

bathymetric data, the 1978 COE topographic survey 

data, and the 1993 and 1996 COE bathymetric data for 

several range lines indicated consistency among the 

data sets (see figs. 8-13 in the "Supplemental Information" section). Therefore, it is believed that both the 

USGS and COE 1996 bathymetric data sets provide 

representative lake-bottom elevation information.

Estimation of Bottom-Sediment 

Thickness, Volume, and Mass

Total bottom-sediment volume (sediment plus 

water and gases) in Hillsdale Lake was estimated using 

a partitioning approach in which the conservation-pool 

surface area of the lake was divided into in-channel and 

out-of-channel components. The channels were 

divided further into segments as determined by the 

locations where the bathymetric range lines intersect 

the channels. The range-line intersections served as the

end points for the channel segments (fig. 2). Likewise, 

the out-of-channel component was divided further into 

three lake partitions as guided by bottom-sediment 

thickness information. The out-of-channel lake partitions consist of the Big Bull Creek arm (including Rock 

Creek), the Little Bull Creek arm, and the main body of 

the lake near the dam (including Wade Branch and 

Scott Branch). Respectively, the out-of-channel lake 

partitions were identified as B, L, and D (fig. 2). Bottom-sediment volume was computed for all 

components as the total surface area multiplied by the 

mean thickness of the lake-bottom sediment. The inand out-of-channel results then were combined to provide an estimate of the total volume of bottom sediment 

in the lake.

The mean thickness of the lake-bottom sediment 

was estimated using the coring data for the out-ofchannel sites and the bathymetric data for the in-channel sites. Because the bathymetric data have an accuracy of about ± 0.25 ft, the bathymetric methodology 

was not considered sensitive enough to reliably measure out-of-channel sediment deposits that may only be 

a few hundredths of a foot thick. Conversely, the bathymetric data were considered to be the best source of 

information available for the in-channel thickness estimates given the limitation (described in the following 

paragraph) associated with the use of a gravity corer to 

sample soft lake-bottom sediment.

With a gravity corer, a phenomenon referred to as 

"core shortening" results in a recovered sediment-core 

sample that may be only about one-half of the actual 

thickness of sediment penetrated (Emery and Hulsemann, 1964). Core shortening is caused by the friction 

of the sediment against the inner wall of the sample 

tube as the corer penetrates the sediment (Emery and 

Hulsemann, 1964; Hongve and Erlandsen, 1979; 

Blomqvist, 1985; Blomqvist and Bostrom, 1987). In 

"normal" lake-bottom sediment at Hillsdale Lake, 

which is characterized by uniform texture with 

decreasing water content at depth, core shortening 

results in a core sample that provides a thinned but 

complete representation of all of the sediment layers 

that were penetrated (Emery and Hulsemann, 1964; 

Hongve and Erlandsen, 1979). Because, as the corer 

enters the sediment, there is a lag phase before initiation of core shortening (Blomqvist, 1985), the phenomenon is not considered to be a significant factor for the 

typically thin sediment layer encountered at the 

out-of-channel coring sites. However, at the in-channel 

sites where the sediment layer is thicker, substantial

Methodology 7
core shortening was observed. Therefore, the bathymetric data provided the best estimate of actual bottom-sediment thickness in the submerged channels.

Bottom-sediment thickness in the submerged 

channels was estimated at the sites where COE bathymetric range lines intersect the channels (fig. 2). At 

each range-line site (that is, a channel-segment end 

point), bottom-sediment thickness was computed as the 

difference between the mean 1996 and the mean 1978 

(pre-impoundment) channel-bed elevation. The mean 

1996 channel-bed elevation was determined using 

either USGS or COE bathymetric data depending on 

which data set provided the most complete information 

for the channel. Each channel segment was assigned a 

bottom-sediment thickness computed as the mean of 

the bathymetry-derived sediment thicknesses for the 

two range-line sites that defined the segment. Channel 

segments with the edge of the conservation pool as 

their upstream limit were assumed to have no sediment 

accumulation at these locations. This assumption is 

based on bathymetric evidence that indicates little or 

no sediment deposition in the upstream-most reaches 

of the tributaries. For example, the Big Bull Creek, Little Bull Creek, and Rock Creek channels had little if 

any sediment deposition at their upstream-most 

range-line sites (fig. 2). The most probable explanation 

for this condition is that the stream velocity at these 

sites is sufficiently high to transport incoming sediment 

farther downstream where eventually it is deposited.

Channel widths were estimated using the 1978 

topographic survey data and the 1996 bathymetric data. 

The channel width at each range-line site was estimated only for the sediment-filled part of the channel 

as opposed to the entire bankfull channel. The channel 

length for each channel segment was estimated by digitizing the channels from USGS l:24,000-scale topographic quadrangles and intersecting the bathymetric 

range lines using geographic-information-system 

software.

The sediment-thickness, channel-width, and channel-length data were used to estimate the bottom-sediment volume for each channel segment. Then, the 

segment volumes were summed to estimate the volume 

of bottom sediment in each channel as well as the total 

in-channel bottom-sediment volume for the lake.

The total mass (dry weight) of bottom sediment in 

the lake was estimated using the same lake components 

as described previously. Using the representative bulk 

density for bottom sediment at each of the in-channel 

coring sites, a mean bulk density was computed for

each channel segment and used to convert bottom-sediment volume to bottom-sediment mass. Total in-channel bottom-sediment mass then was estimated as the 

sum of the sediment mass estimated for the individual 

channel segments. Because few bulk-density values 

were estimated for the out-of-channel coring sites, 

additional bulk-density estimates were computed using 

a regression-derived relation between bulk density and 

percent moisture content. A mean bulk density was 

computed for bottom sediment in out-of-channel lake 

partitions B and L and used to convert bottomsediment volume to bottom-sediment mass. Because 

no bulk-density information was available for 

out-of-channel sites in partition D, an estimated mean 

bulk density was derived using the relation of mean 

in-channel to out-of-channel bulk densities in partitions B and L. A comparison showed that out-of-channel bulk densities were an average of 7.5 percent 

greater than in-channel bulk densities in lake partitions 

B and L. Therefore, the mean bulk density for 

out-of-channel sites in partition D was computed as the 

mean of the in-channel sites plus 7.5 percent.

Because it was not feasible to accurately distinguish annual layers of sediment deposition in the core 

samples, mean annual sediment deposition was estimated by dividing the total mass of bottom sediment by 

the number of years of deposition. Because the reservoir began filling in September 1981, about 15 years of 

sediment deposition had occurred in the lake at the time 

the core and bathymetric data were collected during the 

summer and fall of 1996. Therefore, mean annual sediment deposition was estimated as the total mass of bottom sediment divided by 15.

Estimation of Phosphorus Loads

The total mass of phosphorus (dry weight of total 

phosphorus) in the lake-bottom sediment was estimated as bottom-sediment mass multiplied by the 

mean total phosphorus concentration. The in- and 

out-of-channel components of the lake-bottom sediment were estimated separately and then summed to 

provide an estimate of the total mass of phosphorus in 

the sediment. Mean annual phosphorus loading to the 

bottom sediment was estimated as the total mass of 

phosphorus divided by 15.

The mean annual load (mass) of phosphorus added 

to the lake from point-source discharges was estimated 

on the basis of water-quality and flow data obtained 

from JCED and KDHE for the five largest point

8 Analysis of Bottom Sediment to Estimate Nonpoint-Source Phosphorus Loads for 1981-96 in Hillsdale Lake, Northeast Kansas
sources within the Hillsdale Basin. Included were the 

wastewater-treatment facilities at Edgerton, Gardner, 

and the Johnson County New Century AirCenter as 

well as the wastewater lagoons at Connestoga Mobile 

Home Park and Lone Elm Estates (fig. 1).

The annual amount of total phosphorus exiting the 

lake was estimated using available COE water-quality 

data on total phosphorus concentrations in the lake outflow and available USGS data on the quantity of flow. 

The flow-weighted, mean total phosphorus 

concentration and the mean annual discharge were 

determined and then multiplied to provide an estimate 

of the total phosphorus leaving the lake each year.

The mean annual load of total phosphorus contributed from nonpoint sources was estimated using the 

following mass balance:

(4)

where NPSL is the mean annual nonpoint-source load

(in kilograms), 

PSL is the mean annual point-source load (in

kilograms),

OFL is the mean annual outflow load (in kilograms), and 

SL is the mean annual lake-bottom sediment

load (in kilograms).

Lacking the data to reliably quantify the residence or 

storage time of phosphorus in the streams downstream 

from the point sources, all phosphorus from the point 

sources was assumed to be transported to Hillsdale 

Lake each year. The temporal variability of phosphorus 

concentrations and storage in the lake-water column 

was assumed to be neglible. Therefore, the water-column component in the mass balance was considered 

insignificant relative to the other components and was 

not included.

SEDIMENT DEPOSITION IN HILLSDALE 

LAKE

Estimation of the total and mean annual sediment 

deposition in Hillsdale Lake was a multistep process. 

Initially, sediment-core and bathymetric data were collected to quantify bottom-sediment thickness in the 

lake. Sediment cores were collected both in and outside 

of the submerged stream channels (fig. 2).

Bathymetry-derived, in-channel bottom-sediment 

thicknesses (table 1 and fig. 3) were used to estimate

Table 1. In-channel bottom-sediment thickness 

estimated from 1996 bathymetry and 1978 

topographic information at bathymetric range-line sites 

in Hillsdale Lake

Bathymetric 

range-line site, in 

upstream-todownstream 

order (fig. 3)

10 

9

6al

6C1

5

4

16

15

14

13

1

18

3

12

2

8

7

Submerged channel

Big Bull Creek 

do.

do.

do. 

do.

do.

do.

Little Bull Creek

do.

do.

do.

do.

Wade Branch

do.

Scott Branch

do.

Rock Creek

do.

Bottomsediment 

thickness, 

in feet

2.3 

10.3

5.6

5.5 

8.0

5.4

5.6

0

6.7

4.6

4.5

5.1

7.0

5.1

3.8

9.6

1.0

7.9

'Range line 6 crosses the Big Bull Creek channel three times. 

Sites 6a, 6b, and 6c are the upstream, intermediate, and downstream 

crossings, respectively.

the mean bottom-sediment thickness for each channel 

segment. At each bathymetric range-line site, bottom-sediment thickness was computed as the differ 

ence between the 1996 and the 1978 (preimpoundment) mean channel-bed elevations. A comparison of sediment thickness using the 1993 and 1996 

bathymetry at 10 range-line sites indicated that about 

13 percent of that thickness was deposited in the 

channels after 1993. This converts to a mean annual 

depositional rate of about 4.3 percent of the total thickness for 1994-96 as compared to 7.3 percent for 

1981-93. However, the difference could be due simply 

to 1 or 2 years of exceptionally large or small deposition. A longitudinal view of sediment deposition in the 

Big Bull Creek and Little Bull Creek channels is proSediment Deposition in Hillsdale Lake 9
95°OT 38°45'i 

59' 57' 55' 53' 94°51'

43'

41

38°39'

RC-410.15)

Rock Creek RC-3<o.i5) 

8

BB-4 (0.65)

BB-20 (0.08) 

BB-910.30)

Wade Branch 18

Hillsdale 

D-3 Dam

(<0.02)

Base from U.S. Geological Survey digital data, 1:24.000,1973

Lambert Conformal Conic projection

Standard parallels 33° and 45°, central meridian 98°15'

3 MILES

3 KILOMETERS

EXPLANATION

BB-17 

(0.25)

Extent of Hillsdale Lake at conservation-pool 

elevation (917 feet above sea level)

Bathymetric range line and number Established by 

U.S. Army Corps of Engineers

Out-of-channel sediment-coring site and number 

Number in parentheses ( ) is bottom-sediment 

thickness, in feet

7.9

| | Bathymetric range-line site Number is bottomsediment thickness, in feet, as estimated from 

1996 bathymetric survey and 1978 topographic 

information

Figure 3. Estimated bottom-sediment thickness in Hillsdale Lake, 1996.

10 Analysis of Bottom Sediment to Estimate Nonpoint-Source Phosphorus Loads for 1981-96 in Hillsdale Lake, Northeast Kansas
Bathymetric range-line site (fig. 3)

Upstream end of 10 9 6a6b 6c 5 4 Hillsdale 

conservation pool I Dam

920 n/Jri

915-

910-

<D

JD 905-

03

w 900-

<D

o 895-

JQ 

O3

- 890-

<D

nnr

C OOU 

g 880-

03

> 875-

UJ 870-

865-

PKH

917

"*%

""" ^^^ 907.9

** ». ^*~ ~ P- - _ _^06-5 905.8

905.6*^ ^ ^ "" ~ ~ * * 5.04'6 1996 mean

"" >. 900,2 OQQ^I^ channel-bed 

"" >. ^ ^ - ' -^SS9"' "" ^^898.7 / elevation

^ "* " " " ^ x " *. /

896.2 x » <

^ s^ ' ^ ^890.9

890.7 "" - ^ ^ v

/

** ^ ^ *^* fi

885.5 x ^ x ^

cnannei-oea x ^ x

elevation x N N

x S x 872.6 , 866.6

v *. ^ (extrapolated)

^ x " - - ^. _\

86?

| | | | | | | (extrapolated) ^-=^,

-915

-910

-905

-900

-895

-890

QOC

 ODD

DDfl

 ooU

-875

-870

-865

RRH

90.000 80,000 70,000 60.000 50,000 40,000 30.000 20,000

Distance along channel upstream from Hillsdale Dam, in feet

EXPLANATION

Bottom-sediment thickness estimated as the difference 

between 1996 and 1978 (pre-impoundment) mean 

channel-bed elevations

Figure 4. Estimated bottom-sediment thickness in the Big Bull Creek channel of Hillsdale Lake, 1996.

10.000

vided in figures 4 and 5, respectively. Table 2 provides 

the estimated channel length, mean channel width, 

mean bottom-sediment thickness, and bottomsediment volume for each channel segment.

Bottom-sediment thicknesses measured in sediment-core samples collected at 31 out-of-channel sites 

are provided in table 3 and figure 3. Because of the 

atypically thick sediment encountered (1.23 ft) at 

site D-l and the proximity to a small tributary of the 

main Little Bull Creek channel, there is uncertainty as 

to whether site D-l is more representative of in- or 

out-of-channel conditions. Therefore, site D-l was 

excluded from the calculation of mean sediment thickness for the out-of-channel sites.

To calculate mean values for the out-of-channel 

bottom-sediment thicknesses, the six cores with a 

thickness listed as less than 0.02 ft were assigned a 

value of 0.01 ft. The out-of-channel lake-bottom sediment ranged in thickness from less than 0.02 to 0.89 ft, 

with a mean sediment thickness of 0.24 ft. In general, 

the out-of-channel sediment appeared to be thickest in 

the Big Bull Creek and Little Bull Creek arms of the 

lake and thinnest in the main body near the dam (fig. 3).

Table 4 provides the estimated area, mean bottom-sediment thickness, and bottom-sediment volume for each 

out-of-channel lake partition.

The total volume of bottom sediment in the lake 

was estimated as the sum of the bottom-sediment volumes determined for the in-channel and out-of-channel 

components of the lake (table 5). The total in- and 

out-of-channel bottom-sediment volumes were 

51,300,000 and 40,100,000 ft3, respectively. Therefore, the total estimated volume of bottom sediment in 

the lake was 91,400,000 ft3 or about 2,100 acre-ft. In 

comparison, the COE, using bathymetry only, estimated the total bottom-sediment volume in 1993 to be 

1,928 acre-ft (Phil Snell, U.S. Army Corps of Engineers, oral commun., 1997). The 2,100 acre-ft of sediment occupies about 3 percent of the lake's original 

water-storage capacity of 68,000 acre-ft at conservation pool.

Respectively, the in- and out-of-channel components represent about 6 and 94 percent of the total conservation-pool surface area of the lake. However, the 

in-channel component represents about 56 percent of 

the total volume of bottom sediment. Thus, as noted by

Sediment Deposition in Hiiisdaie Lake 11
Bathymetric range-line site (fig. 3)

Upstream end of 16 15 1413 \Hillsdale 

conservation pool 1 Dam 

920 1 ' non

915-

910-

905-

900-

895-

890-

885-

880-

875-

870-

865-

RKn 

^917

^ ^ ^

"" ^ ^ ^908.4

908.4 0^_ ^_ ^ ^ 19g6 megn

"> ^ ~" "~ ~- ^ 901.3 channel-bed

"" ». x ^ / elevation

^ """ . ^ ^

894.6 ^ ^ ^ ^ x

^7- X ^

1978 mean / ^ "" ^ ^ ^84.7 

channel-bed v -^ _^ "" - ^882.1

elevation >»^ N ^

880.1 - - 

877.6 x », ^ ^872.9

V X_

870.1 "" >-. x

(extrapolated) ' ^

867.8 ^.

865 /^

I I I I I {(extrapolated)

-915

-910

-905

-900

-895

-890

-885

_ 

 

oon OoU

-875

>-870

i-865

 RKH

70,000 60,000 50,000 40.000 30.000 20.000 10.000 

Distance along channel upstream from Hilisdale Dam, in feet

EXPLANATION

Bottom-sediment thickness estimated as the difference 

between 1996 and 1978 (pre-impoundment) mean 

channel-bed elevations

Figure 5. Estimated bottom-sediment thickness in the Little Bull Creek channel of Hilisdale Lake, 1996.

Thornton and others (1990), initial sediment deposition 

is greatest in the submerged channels.

Bottom-sediment mass was estimated as the bottom-sediment volume multiplied by the mean bulk 

density of the sediment. Bulk densities were estimated 

at 18 in-channel (table 6) and 12 out-of-channel 

(table 7) sites in the lake (fig. 6). Of the 12 out-of-channel sites, bulk-density values for 8 sites were estimated 

using a relation between bulk density and percent 

moisture content. A statistical analysis was performed 

using 19 sites for which bulk-density and percentmoisture-content information was available. For sites 

having data for multiple depth intervals, the uppermost 

depth interval was used on the assumption that it would 

most closely approximate conditions at the out-ofchannel sites for which bulk density was being estimated. A Pearson's correlation coefficient of -0.94 

(R2 = 0.89) was calculated, thus indicating a strong 

inverse relation between bulk density and percent

moisture content (see fig. 35 in the "Supplemental 

Information" section). A regression analysis was used 

to determine the following relation:

= -l.07M + 96.68, (5)

where BD is the bulk density, and

M is the percent moisture content. This relation was used to estimate the bulk density 

at the eight out-of-channel sites. 

Estimated bulk densities ranged from a mean of

28.0 lb/ft3 at site D-2 (in-channel site) to 59.9 lb/ft3 at 

site BB-4 (out-of-channel site), with an overall mean

of 42.8 lb/ft3 . The range of estimated bulk densities is 

consistent with bulk densities estimated at nine sites 

within the lake by COE in 1993 (Al Coop, U.S. Army 

Corps of Engineers, written commun., 1996). COE

bulk densities ranged from 30.0 to 50.1 lb/ft3 . In

12 Analysis of Bottom Sediment to Estimate Nonpoint-Source Phosphorus Loads for 1981-96 in Hilisdale Lake, Northeast Kansas
Table 2. Estimated length, mean width, mean bottom-sediment thickness, and bottom-sediment volume in 

submerged stream-channel segments in Hillsdale Lake, 1996

[length and volume values have been rounded to three significant figures]

Channel segment 

(fig. 3)

Channel 

length, in feet

Mean channel 

width, 

in feet

Mean bottomsediment 

thickness, 

in feet

Bottom-sediment

volume1 , 

in cubic feet

Big Bull Creek

Upstream end of

conservation pool to 16,300

range line 10 

Range lines 10 to 9 

Range lines 9 to 6a 

Range lines 6a to 6c 

Range lines 6c to 5 

Range lines 5 to 4 

Range line 4 to dam

Little Bull Creek

Upstream end of

conservation pool to 13,600

range line 16 

Range lines 16 to 15 

Range lines 15 to 14 

Range lines 14 to 13 

Range line 13 to dam

Wade Branch

Upstream end of

conservation pool to 5,010 

range line 18

Range line 18 to

confluence with Big 11 ^00 

Bull Creek

Scott Branch

Upstream end of

conservation pool to 569 

range line 12

Range line 12 to

confluence with Big 12,000 

Bull Creek

Rock Creek

Upstream end of

conservation pool to 893

range line 8 

Range line 8 to

confluence with Big 11,100

Bull Creek

30

20

40

50

95

100

15

30

1.2

3.5

6.1

1.9

6.7

.5

4.5

587,000

13,300

8,440

9,880

9,750

14,200

13,900

45

50

55

65

55

60

6.3

8.0

6.4

6.7

5.5

5.6

3,770,000

3,380,000

3,480,000

4,250,000

4,300,000

4,670,000

18,300

18,300

5,680

12,100

35

55

60

60

3.4

5.7

4.6

4.8

2,180,000

5,740,000

1,570,000

3,480,000

701,000

3,540,000

103,000

8,040,000

6,700

1,500,000

'Bottom-sediment volume is calculated as channel length multiplied by mean channel width multiplied by mean bottom-sediment 

thickness.

Sediment Deposition in Hillsdale Lake 13
Table 3. Bottom-sediment thickness measured in 

core samples collected at out-of-channel sites in 

Hillsdale Lake, 1996

[<, less than]

Out-ofchannel 

site 

(fig. 3)

BB-1

BB-2

BB-4

BB-5

BB-6

BB-7

BB-8

BB-9

BB-1 6

BB-1 7

BB-1 8

BB-19

BB-20

D-l

D-3

D-5

D-6

LB-1

LB-2

LB-3

LB-4

LB-5

LB-6

LB-7

LB-1 6

LB-1 7

RC-3

RC-4

SB-1

SC-1

WB-1

Date 

sampled 

(month/ 

day/ 

year)

07/17/96

07/17/96

09/05/96

09/05/96

09/05/96

09/05/96

09/05/96

09/16/96

10/28/96

10/28/96

11/01/96

11/01/96

11/01/96

07/16/96

08/28/96

10/28/96

10/28/96

07/16/96

06/25/96

08/29/96

08/29/96

08/29/96

09/04/96

09/04/96

10/28/96

10/28/96

10/08/96

10/08/96

09/05/96

09/16/96

09/16/96

Latitude 

(decimal 

degrees)

38.70555

38.69129

38.68106

38.68581

38.69659

38.68620

38.68619

38.67375

38.67183

38.68470

38.70161

38.69171

38.67809

38.65906

38.65651

38.66299

38.65647

38.70164

38.68532

38.68102

38.67660

38.66960

38.69201

38.70742

38.68670

38.69888

38.70462

38.70547

38.69638

38.64858

38.66194

BottomLongitude sediment 

(decimal thickness, 

degrees) in feet

94.96526

94.94543

94.93949

94.93903

94.95620

94.94874

94.94878

94.92407

94.92141

94.93427

94.96529

94.95172

94.93286

94.90649

94.91091

94.90653

94.91346

94.88448

94.90209

94.90643

94.91189

94.91153

94.89300

94.88062

94.89798

94.88793

94.97537

94.97489

94.94357

94.92868

94.93664

0.15

.45

.65

<.02

.20

<.02

.02

.30

.32

.25

.45

.24

.08

1.23

<.02

.18

.02

.15

.20

<.02

<.02

.08

.89

.72

.54

.11

.15

.15

.45

<.02

.06

Table 4. Estimated area, mean bottom-sediment 

thickness, and bottom-sediment volume in 

out-of-channel lake partitions of Hillsdale Lake, 1996

[area and volume values have been rounded to three significant figures]

Out-ofchannel

lake 

partition

(fig-2)

B 

D 

L

Area, in 

square feet

77,300,000

72,300,000

37,200,000

Mean 

bottomsediment 

thickness, 

in feet

0.26 

.05

.44

Bottomsediment 

volume1 , in 

cubic feet

20,100,000

3,620,000

16,400,000

'Bottom-sediment volume calculated as out-of-channel area 

multiplied by mean bottom-sediment thickness.

Table 5. Estimated bottom-sediment volume for 

Hillsdale Lake, 1996

[all values have been rounded to three significant figures]

Lake component 

(fig-2)

Out-of-channel

In-channel

Big Bull Creek 

Little Bull Creek 

Wade Branch 

Scott Branch 

Rock Creek

Total for inchannel 

component

Total for lake

Bottomsediment volume, 

in cubic feet

40,100,000

24,400,000

13,000,000

4,240,000

8,140,000

1,510,000

51,300,000

91,400,000

Percentage 

of total 

bottomsediment 

volume

43^9

26.7

14.2

4.6

8.9

1.7 ~56T

100

general, the bulk density of channel sediment was highest in the upstream parts of the lake and lowest downstream near the dam. For example, the bulk density of 

bottom sediment in the Big Bull Creek channel ranged

from a mean of 49.4 lb/ft3 at upstream site BB-13 to a

mean of 28.8 lb/ft3 at site D-4 near the dam (fig. 6). 

The out-of-channel sites did not exhibit the same 

upstream-to-downstream trend of decreasing bulk 

densities.

14 Analysis of Bottom Sediment to Estimate Nonpoint-Source Phosphorus Loads for 1981-96 in Hillsdale Lake, Northeast Kansas
Table 6. Estimated bulk density of bottom sediment at 

in-channel sites in Hillsdale Lake, 1996

Table 7. Estimated bulk density of bottom sediment at 

out-of-channel sites in Hillsdale Lake, 1996

[bulk-density values have been rounded to three significant figures] [bulk-density values have been rounded to three significant figures]

In-channel

site

(fig. 6)

BB-10

BB-10

BB-11

BB-11

BB-12

BB-12

BB-13

BB-13

BB-14

BB-14

BB-15

BB-15

D-2

D-2

D-2

D-2

D-2

D-4

D-4

LB-8

LB-8

LB-9

LB-9

LB-10

LB-10

¥ UJ TJ 1111

LB-11

LB-13

LB-13

LB-14

LB-14

LB-15

LB-15

RC-2

RC-2

SC-3

WB-2

WB-2

Sample depth,

in feet

0.58-1.16

1.74-2.32

0.68-1.36

2.04-2.72

0.72-1.44

2.16-2.88

1.01-2.02

3.03-4.04

0.83-1.66

2.49-3.32

0.86-1.72

2.58-3.44

0-0.68

0.68-1.36

1.36-2.04

2.04-2.72

2.72-3.40

0.22-0.44

0.66-0.88

0.22-0.44

0.66-0.88

0.69-1.38

2.07-2.76

0.78-1.56

2.34-3.12

fl u. 7Q_1 iy i.joSR 

2.37-3.16

0.48-0.96

1.44-1.92

0.45-0.90

1.35-1.80

0.49-0.98

1.47-1.96

0.98-1.96

2.94-3.92

0.20-0.60

0.52-1.04

1.56-2.08

Bulk density, in

pounds per

cubic foot

35.8

41.9

33.7

39.6

29.0

30.3

47.1

51.7

44.9

52.3

38.2

49.0

21.5

24.7

26.4

31.2

36.5

27.7

29.9

29.6

42.2

40.0

49.9

29.5

40.0

32 _r^> 7i

36.2

31.1

38.0

35.7

37.2

49.1

49.2

44.4

54.7

48.0

34.9

46.6

Out-of- Bulk density,

channel site Sample depth, in pounds per

(fig. 6) in feet cubic foot

BB-1 1 0-0.15 57.1

BB-21 0-0.45 42.6

BB-4 0.16-0.48 59.9

rm DD /cl r\f) jf) co Q \j \j \}.£\j jj.y

BB-91 0-0.30 35.7

BB-1 8 0-0.38 44.8

LB-1 1 0-0.15 58.2

LB-21 0-0.20 53.3

LB-61 0-0.89 30.9

LB-7 0.18-0.54 48.1

LB-16 0-0.52 28.6

SB-1 1 0-0.45 46.9

'Bulk density estimated using a regression equation that expresses

the relation to moisture content.

The total in-channel mass of bottom sediment in

the lake, estimated as the sum of the sediment mass

computed for the individual channel segments (fig. 2),

was 2,136 million Ib. Total out-of-channel bottom-sediment mass, estimated as the sum of the sediment mass

computed for the three lake partitions (fig. 2), was

1,837 million Ib. Therefore, the total estimated mass of

bottom sediment in the lake is 3,973 million Ib of

which about 54 percent is in the submerged channels.

Tables 8 and 9 detail the bottom-sediment mass

estimated for the in- and out-of-channel lake components, respectively. Table 10 provides an overall summary of bottom-sediment mass estimated for the lake.

Annual sediment deposition was estimated by

dividing the total mass of bottom sediment in the lake

by the number of years of deposition (that is, 15). The

mean annual sediment deposition was estimated to be

265 million Ib or 120 million kg.

PHOSPHORUS IN HILLSDALE LAKE

Concentrations of total phosphorus in the lake-bottom sediment were determined for both in- and

out-of-channel sites. To facilitate comparisons, a

depth-integrated mean was calculated (excluding the

Phosphorus in Hillsdale Lake 15
95°OV 38°45'i 

59' 57' 55' 531 94°51'

43'

41

38°39'

Rock Creek

g \ RC-2 (49.6)

SB-K46.9)* Hiilsdale ijl <34.6] 

Lake

BB-9 (35.7)* 

... , D . BB-12<29.7)

Wade Branch WB_2

(40.8)

LB-9 (45.0)

)

LB-6(30.9)* 

LB-16 (28.6)

Hiilsdale 

Dam

Base from U.S. Geological Survey digital data. 1:24,000,1973

Lambert Conformal Conic projection

Standard parallels 33° and 45°, central meridian 98°15' 3 KILOMETERS

3 MILES

EXPLANATION

BB-13 

(37.8) (

BB-4 

(59.9)O

Extent of Hiilsdale Lake at conservation-pool 

elevation (917 feet above sea level)

Bathymetric range line and numbei Established 

by U.S. Army Corps of Engineers

In-channel sediment-coring site and number 

Number in parentheses () is mean bulk density, in 

pounds per cubic foot

Out-of-channel sediment-coring site and number 

Number in parentheses () is mean bulk density, in 

pounds per cubic foot

Asterisk indicates that sediment bulk density, in 

pounds per cubic foot, was estimated using a 

regression equation

Figure 6. Estimated bulk density of bottom sediment in Hiilsdale Lake, 1996.

16 Analysis of Bottom Sediment to Estimate Nonpoint-Source Phosphorus Loads for 1981-96 in Hiilsdale Lake, Northeast Kansas
Table 8. Estimated bottom-sediment volume, mean bulk density, and mass in submerged 

channels of Hillsdale Lake, 1996

[all values have been rounded to three significant figures]

Channel segment

(fig. 2)

Big Bull Creek

Upstream end of conservation pool to range line 10

Range lines 10 to 9

Range lines 9 to 6a

Range lines 6a to 6c

Range lines 6c to 5

Range lines 5 to 4

Range line 4 to dam

Little Bull Creek

Upstream end of conservation pool to range line 16

Range lines 16 to 15

Range lines 15 to 14

Range lines 14 to 13

Range line 1 3 to dam

Bottom-sediment 

volume, in cubic 

feet

587,000

3,770,000

3,380,000

3,480,000

4,250,000

4,300,000

4,670,000

0

2,180,000

5,740,000

1,570,000

3,480,000

Mean bulk 

density, in 

pounds per 

cubic foot

49.4

49.4

47.4

44.9

40.7

33.8

29.3

45.0

45.0

42.9

35.6

32.0

Bottom-sediment 

mass1 , in pounds

29,000,000

186,000,000

160,000,000

156,000,000

173,000,000

145,000,000

137,000,000

0

98,100,000

246,000,000

55,900,000

111,000,000

Wade Branch

Upstream end of conservation pool to range line 18 701,000

Range line 18 to confluence 

with Big Bull Creek 3,540,000

Scott Branch

Upstream end of conservation pool to range line 12 103,000

Range line 12 to confluence 

with Big Bull Creek 8,040,000

Rock Creek

Upstream end of conservation pool to range line 8 6,700

Range line 8 to confluence 

with Big Bull Creek 1,500,000

40.8

40.8

48.0

48.0

49.6

49.6

28,600,000

144,000,000

4,940,000

386,000,000

332,000

74,400,000

'Bottom-sediment mass is calculated as bottom-sediment volume multiplied by mean bulk density.

Phosphorus in Hillsdale Lake 17
Table 9. Estimated bottom-sediment volume, mean 

bulk density, and mass in out-of-channel lake 

partitions of Hillsdale Lake, 1996

[all values have been rounded to three significant figures]

Out-ofchannel 

lake 

partition 

(fig- 2)

B

D

L

Bottomsediment 

volume, in 

cubic feet

20,100,000

3,620,000

16,400,000

Mean bulk

density, in 

x pounds 

per cubic 

foot

48.7

38.8

43.8

Bottom- 

= sediment 

mass1 , in 

pounds

979,000,000

140,000,000

718,000,000

'Bottom-sediment mass is calculated as bottom-sediment volume 

multiplied by mean bulk density.

Table 10. Estimated bottom-sediment mass in 

Hillsdale Lake, 1996

[all values have been rounded to three or four significant figures]

Percentage 

of total 

bottomsediment 

mass

Lake component 

(fig- 2)

Bottom-sediment 

mass, in pounds

Out-of-channel

In-channel

Big Bull Creek 

Little Bull Creek 

Wade Branch 

Scott Branch 

Rock Creek

Total for in-channel 

component

Total for lake

1,837,000,000 46.2

986,000,000

511,000,000

173,000,000

391,000,000

74,700,000

24.8

12.9

4.4

9.8

1.9

2,136,000,000

3,973,000,000

53.8

100

duplicate samples) to provide a representative phosphorus concentration for each site sampled (fig. 7). The 

in-channel phosphorus concentrations (table 11) 

showed no apparent trend with depth. Likewise, there 

was no apparent upstream-to-downstream trend 

observed for either the in- or out-of-channel (table 12) 

phosphorus concentrations. Overall, the depth-integrated, mean phosphorus concentrations for the 

in-channel bottom sediment ranged from 410 to 

810 mg/kg, with a mean of 610 mg/kg. The depth-integrated, mean phosphorus concentrations for the 

out-of-channel bottom sediment ranged from 210 to

710 mg/kg, with a mean of 400 mg/kg (excluding 

site D-l due to uncertainty as to whether site D-l is 

more representative of in- or out-of-channel conditions). These results are in general agreement with 

COE phosphorus concentration data determined for 

seven sites within the lake in 1993 and(or) 1995 (Al 

Coop, U.S. Army Corps of Engineers, written commun., 1996). For COE sites having multiple-date phosphorus concentration data, the mean phosphorus 

concentration was calculated as a basis for comparison 

with the single-date USGS phosphorus concentration 

data. The adjusted COE phosphorus concentration data 

ranged from 470 to 900 mg/kg, with a mean of 680 

mg/kg. Sedimentary rocks may contain phosphorus 

concentrations in the range of about 280 to 730 mg/kg 

(Hem, 1985). Thus, a substantial part of the observed 

phosphorus concentrations in the Hillsdale Lake bottom sediment may originate from soils and limestone 

and shale bedrock within the basin.

For quality-assurance purposes, 27 duplicate bottom-sediment samples were analyzed for total phosphorus concentration. In comparison, the duplicates 

differed from the original samples by an average of 

+9 percent. This is considered to be within the range of 

acceptable variability for the analysis of total phosphorus concentrations in bottom sediment.

The total mass of phosphorus in the lake-bottom 

sediment was estimated by calculating the mass of 

phosphorus separately for the in- and out-of-channel 

components of the lake and then summing. The 

in-channel mass of phosphorus was estimated as the 

total in-channel mass of bottom sediment multiplied by 

the mean phosphorus concentration for all the in-channel sites (that is, 610 mg/kg). Likewise, the out-ofchannel mass of phosphorus was estimated as the total 

out-of-channel mass of bottom sediment multiplied by 

the mean phosphorus concentration for all the 

out-of-channel sites (that is, 400 mg/kg). The mean 

phosphorus concentrations were used given that no 

upstream-to-downstream trend in phosphorus concentrations was observed in the lake-bottom sediment. The 

total in- and out-of-channel mass of phosphorus was 

estimated to be 591,000 and 333,000 kg, respectively. 

Therefore, the total mass of phosphorus in the bottom 

sediment was estimated to be 924,000 kg, of which 

64 percent is in the submerged channels. The mean 

annual load of phosphorus in the bottom sediment was 

estimated to be 62,000 kg for 1981-96.

18 Analysis of Bottom Sediment to Estimate Nonpoint-Source Phosphorus Loads for 1981-96 in Hillsdale Lake, Northeast Kansas
95°OV 38°45'i 

59' 57' 55' 53' 94°51'

43'

4V

38°39'

Rock Creek

Hillsdale

(660) Dam

(410)

Base from U.S. Geological Survey digital data, 1:24.000.1973

Lambert Conformal Conic projection

Standard parallels 33° and 45°, central meridian 98°15'

3 MILES

3 KILOMETERS

EXPLANATION

Extent of Hillsdale Lake at conservation-pool 

elevation (917 feet above sea level)

Bathymetric range line and number

U.S. Army Corps of Engineers

-Established by

BB-10, 

(620) In-channel sediment-coring site and number Number 

in parentheses () is depth-integrated mean total phosphorus 

concentration in lake-bottom sediment, in milligrams per 

kilogram

Out-of-channel sediment-coring site and number Number 

in parentheses () is total phosphorus concentration or depthintegrated mean total phosphorus concentration in lake-bottom 

sediment, in milligrams per kilogram

Figure 7. Total phosphorus concentrations in bottom sediment of Hillsdale Lake, 1996.

BB-4 

(300)

Phosphorus in Hillsdaie Lake 19
Table 11. Total phosphorus concentrations and percent moisture content of bottom sediment at in-channel sites 

in Hillsdale Lake, 1996

[all values have been rounded to two significant figures; mg/kg, milligrams per kilogram; dup, duplicate sample]

In-channel

site

(fig- 7)

BB-10

BB-11

Total phosphorus 

concentraSample depth, 

in feet

0-0.58

0-0.58dup

0.58-1.16

0.58-1. 16dup

1.16-1.74

1.16-1.74dup 

1.74-2.32

1.74-2.32dup

2.32-2.90

2.32-2.90dup

0-0.68

0.68-1.36

1.36-2.04

2.04-2.72

2.72-3.40 

1 Depth-integrated mean for 

sites BB-10 and BB-11

BB-12 0-0.72

0.72-1.44

1.44-2.16

2.16-2.88 

2.88-3.33

Depth-integrated mean

BB-13 0-1.01

1.01-2.02

2.02-3.03

3.03-4.04 

4.04-5.05

Depth-integrated mean

BB-14 0-0.83

0.83-1.66

1.66-2.49

2.49-3.32 

3.32-3.87

Depth-integrated mean

tion 

(mg/kg)

660

460

630

660

580

550 

700

610

600

510

540

490

660

730

580

620 

650

480

600

600 

500

570

610

610

660

670 

680

650

520

530

580

580 

730

590

Percent

moisture 

content

64

64

58

58

54

54 

54

54

44

44

63

59

55

53

45 

67

61

58

58 

52

54

46

43

43 

40

52

48

46

43 

47

Total phosphorus 

In-channel concentrasite Sample depth, 

(fig. 7) in feet

BB-15 0-0.86

0.86-1.72

0.86-1. 72dup

1.72-2.58

2.58-3.44

2.58-3.44dup

3.44-4.30 

1 Depth-integrated mean

D-2 0-0.68

0.68-1.36

0.68-1. 36dup

1.36-2.04

1.36-2.04dup

2.04-2.72

2.04-2.72dup 

2.72-3.40 

2.72-3.40dup 

1 Depth-integrated mean

D-4 0-0.22

0.22-0.44

0.22-0.44dup 

0.44-0.66 

0.44-0.66dup

0.66-0.88

0.66-0.88dup

0.88-1.10

0.88-1. lOdup 

1 Depth-integrated mean

LB-8 0-0.22

0.22-0.44

0.44-0.66

0.66-0.88

0.88-1.10 

Depth-integrated mean

tlon 

(mg/kg)

640

790

720

710

650

690

670

690

840

840

850

800

880

840

710 

750 

690

810

630

680

650 

730 

760

710

720

570

530

660

620

670

480

590

480

570

Percent

moisture 

content

61

57

57

50

46

46

45

72

68

68

64

64

62

62

55 

55

70

65

65 

63 

63

61

61

51

51

68

64

56

54

42

20 Analysis of Bottom Sediment to Estimate Nonpoint-Source Phosphorus Loads for 1981-96 in Hillsdale Lake, Northeast Kansas
Table 11. Total phosphorus concentrations and percent moisture content of bottom sediment at in-channel sites 

in Hillsdale Lake, 1996 Continued

In-channel

site

(fig. 7)

LB-9

Sample depth,

in feet

0-0.69

0.69-1.38

1.38-2.07

2.07-2.76

2.76-3.47

Depth-integrated mean

LB-10 0-0.78

0.78-1.56

1.56-2.34

2.34-3.12

3.12-3.62

Total phosphorus

concentration

(mg/kg)

630

600

620

560

640

610

760

770

880

690

690

Percent

moisture

content

57

52

47

41

45

In-channel

site

(fig. 7)

LB-15

Sample depth,

in feet

0-0.49

0.49-0.98

0.98-1.47

1.47-1.96

1.96-2.21

Depth-integrated mean

65

60

55

53

49

RC-1 0-0.50

0.50-1.0

1.0-1.5

1.5-2.0

2.0-2.5

Depth-integrated mean

LB-11 0-0.79

0-0.79dup

0.79-1.58

1.58-2.37

2.37-3.16

3.16-3.94

1 Depth-integrated mean for

750

750

850

690

730

590

740

63

63

57

52

54

44

sites LB-10 and LB-11

LB-13 0-0.48

0.48-0.96

0.48-0.96dup

0.96-1.44

0.96-1. 44dup

1.44-1.92

1.92-2.42

1 Depth-integrated mean

LB-14 0-0.45

0.45-0.90

0.90-1.35

1.35-1.80

1.80-2.24

Depth-integrated mean

610

580

600

580

570

690

550

600

720

700

740

830

700

740

67

59

59

54

54

56

48

58

52

53

53

49

RC-2 0-0.98

0.98-1.96

1.96-2.94

2.94-3.92

3.92-4.90

Depth-integrated mean

SC-2

SC-3

0-0.44

0.44-0.87

0-0.40

0.40-0.80

Depth-integrated mean for

Total phosphorus

concentration

(mg/kg)

470

470

510

560

630

530

460

480

570

560

580

530

480

520

580

550

450

520

460

340

480

330

410

Percent

moisture

content

50

45

44

44

45

48

47

50

47

45

52

48

45

41

34

56

37

54

37

sites SC-2 and SC-3

WB-2 0-0.52

0.52-1.04

1.04-1.56

1.56-2.08

2.08-2.60

Depth-integrated mean

540

600

540

550

390

520

57

55

49

46

35

'Computed without the duplicate samples.

Phosphorus in Hillsdale Lake 21
Table 12. Total phosphorus concentrations and percent moisture content of bottom sediment at out-of-channel 

sites in Hillsdale Lake, 1996

Out-ofchannel

site

(fig. 7)

BB-1

BB-2

Sample depth, 

in feet

0-0.15

0-0.15dup

0-0.22

0-0.22dup 

0.22-0.45

0.22-0.45dup 

1 Depth-integrated mean

BB-4 0-0.33

0.33-0.65

Depth-integrated mean

BB-6

BB-9 

2D-1

0-0.2

0-0.3 

0-0.13

0-0.13dup

0.13-0.68 

0.13-0.68dup

0.68-1.23 

0.68-1.23dup 

1 Depth-integrated mean

Total phosphorus 

concentration 

(mg/kg)

360

360

450

410 

370

360

410

290

300

300

340

480 

680

700

680 

770

620 

600

660

Percent

moisture 

content

37

37

55

55 

46

46

44

36

40

57 

83

83

70 

70

62 

62

Out-ofchannel

site

(fig. 7)

LB-1

LB-2

Sample depth, 

in feet

0-0.15

0-0.15dup

0-0.1

0.1-0.2

Depth-integrated mean

LB-6 0-0.44

0.44-0.89

Depth-integrated mean

LB-7 0-0.36

0-0.36dup

0.36-0.72

0.36-0.72dup 

1Depth-integrated mean

SB-1 0-0.22

0.22-0.45

Depth-integrated mean

Total phosphorus 

concentration 

(mg/kg)

210

220

340

310

330

750

670

710

450

400

410

490

430

470

440

460

Percent

moisture 

content

36

36

41

40

65

58

51

51

42

42

50

43

'Computed without duplicate samples. 

2Site D-l was excluded from the computation of mean total

ESTIMATED ANNUAL PHOSPHORUS 

LOADS FROM NONPOINT SOURCES

Estimation of annual loads of phosphorus from 

nonpoint sources to Hillsdale Lake was accomplished 

using the following mass balance:

NPSL + PSL - OFL + SL, (4)

where NPSL is the mean annual nonpoint-source load

(in kilograms), 

PSL is the mean annual point-source load (in

kilograms),

OFL is the mean annual outflow load (in kilograms), and

phosphorus concentration for the out-of-channel sites due to uncertainty as 

to whether the site is more representative of in- or out-of-channel 

conditions.

SL is the mean annual lake-bottom sediment

load (in kilograms).

Available and(or) newly collected data were used to 

quantify the PSL, OFL, and SL variables in the relation, 

thereby allowing NPSL to be determined. The annual 

load of phosphorus to Hillsdale Lake from point 

sources, computed as the mean of the estimates provided by three previous studies (Montgomery, 1991; 

Camey, 1994; Holt, 1996), was about 5,000 kg. The 

mean annual load of phosphorus deposited in the 

lake-bottom sediment was estimated to be about 

62,000 kg.

The mean annual mass of phosphorus exiting 

Hillsdale Lake was estimated using available data on 

total phosphorus concentrations in the lake outflow and

22 Analysis of Bottom Sediment to Estimate Nonpoint-Source Phosphorus Loads for 1981-96 in Hillsdale Lake, Northeast Kansas
mean annual discharge. COE data on total phosphorus 

concentrations consisted of 43 samples collected during 1984-95 (Al Coop, U.S. Army Corps of Engineers, 

written commun., 1996). Phosphorus concentrations 

ranged from 0.01 to 1.8 mg/L, with a flow-weighted 

mean of 0.07 mg/L. USGS streamflow data for the 

same time period indicated a range in mean annual discharge of 12 to 263 ft3/s, with a mean of 120 ft3/s. The 

mean annual mass of phosphorus (dissolved plus suspended) leaving the lake, calculated as the mean 

phosphorus concentration (0.07 mg/L) multiplied by 

the mean annual discharge (120 ft3/s), was estimated to 

be about 8,000 kg.

By solving equation 4, the mean annual load of 

total phosphorus contributions to the lake from nonpoint sources was estimated to be about 65,000 kg. 

Therefore, of the mean annual total phosphorus load of 

70,000 kg, the contributions from point sources represent about 7 percent and from nonpoint sources, about 

93 percent. Additional study may be helpful in determining the availability of phosphorus as it relates to 

eutrophication processes within the lake.

SUMMARY

Bottom sediment in Hillsdale Lake, northeast Kansas, was analyzed as a means of estimating the annual 

loads of total phosphorus deposited in the lake from 

nonpoint sources. A combination of topographic, 

bathymetric, and sediment-coring data was used to 

estimate the total volume of bottom sediment in the 

lake. Laboratory analyses of the core samples provided 

information on the percent moisture content, bulk density, and phosphorus concentrations of the bottom sediment and were used to estimate the total mass of 

bottom sediment and phosphorus in the lake. Available 

streamflow and water-quality data were used to compute the mean annual mass of phosphorus (dissolved 

plus suspended) exiting the lake as well as the mean 

annual load of phosphorus deposited in the lake from 

point sources. The mean annual load of phosphorus 

from nonpoint sources then was calculated using a 

simple mass balance.

The total volume of bottom sediment in the lake 

was estimated to be 91,400,000 ft3 . The total mass of 

sediment was estimated to be 3,973 million Ib, with a 

mean annual (1981-96) sediment deposition of 

265 million Ib (120 million kg). Of the total sediment 

mass, about 54 percent is in the submerged channels. 

The total mass of phosphorus in the lake-bottom sediment was estimated to be 924,000 kg, with a mean 

annual load of 62,000 kg. The mean annual mass of 

phosphorus (dissolved plus suspended) exiting in lake 

outflow was estimated to be about 8,000 kg. The mean 

annual loads of phosphorus to the lake from point and 

nonpoint sources were estimated to be 5,000 and 

65,000 kg, respectively. Thus, the contribution to the 

total mean annual phosphorus load in Hillsdale Lake 

from point sources is about 7 percent and from nonpoint sources, about 93 percent. Point sources of 

phosphorus in the Hillsdale Lake Basin include wastewater-treatment facilities and wastewater lagoons. 

Nonpoint sources of phosphorus in the basin include 

soils, bedrock, septic systems, feedlots, and cropland.

REFERENCES

Baudo, Renato, Giesy, J.P., and Muntau, Herbert, eds., 1990, 

Sediments chemistry and toxicity of in-place pollutants: Ann Arbor, Michigan, Lewis Publishers, Inc., 

405 p.

Blomqvist, Sven, 1985, Reliability of core sampling of soft 

bottom sediment an in situ study: Sedimentology, 

v. 32, p. 605-612.

Blomqvist, Sven, and Bostrom, Kurt, 1987, Improved sampling of soft bottom sediments by combined box and 

piston coring: Sedimentology, v. 34, p. 715-719.

Bostrom, Bengt, Jansson, Mats, and Forsberg, Curt, 1982, 

Phosphorus release from lake sediments: Archiv fur 

Hydrobiologie Ergebnisse der Limnologie, v. 18, 

p. 5-59.

Carney, C.E., 1994, Hillsdale Lake nutrient loading study for 

total maximum daily load (TMDL) development: 

Topeka, Kansas Department of Health and Environment, 55 p.

Cole, G.E., 1983, Textbook of limnology (3d ed.): Prospect 

Heights, Illinois, Waveland Press, Inc., 401 p.

Emery, K.O., and Hulsemann, J., 1964, Shortening of sediment cores collected in open barrel gravity corers: Sedimentology, v. 3, p. 144-154.

Fishman, M.J., and Friedman, L.C., eds., 1989, Methods for 

determination of inorganic substances in water and fluvial sediments: U.S. Geological Survey Techniques of 

Water-Resources Investigations, book 5, chap. Al, 

545 p.

Gordon, N.D., McMahon, T.A., and Finlayson, B.L., 1992, 

Stream hydrology an introduction for ecologists: 

New York, John Wiley & Sons, 526 p.

Hakanson, L., and Jansson, M., 1983, Principles of lake sedimentology: New York, Springer-Verlag, 316 p.

References 23
Hem, J.D., 1985, Study and interpretation of the chemical 

characteristics of natural water (3d ed.): U.S. Geological Survey Water-Supply Paper 2254, 263 p.

Holt, A.A., 1996, Estimation of 1994 point source and non 

point source phosphorus loading to Hillsdale Lake: 

Shawnee Mission, Kansas, Johnson County Environmental Department, various pagination.

Hongve, Dag, and Erlandsen, A.H., 1979, Shortening of surface sediment cores during sampling: Hydrobiologia, 

v. 65, no. 3, p. 283-287.

Montgomery, J.M., Inc., 1991, Hillsdale Lake nutrient loading study: Wayzata, Minnesota, J.M. Montgomery, Inc., 

various pagination.

National Oceanic and Atmospheric Administration, 1993, 

Climatological data, annual summary Kansas, 1993:

U.S. Department of Commerce, National Oceanic and 

Atmospheric Administration, v. 107, no. 13, p. 8-9.

Putnam, I.E., 1997, Occurrence of phosphorus, other nutrients, and triazine herbicides in water from the Hillsdale 

Lake Basin, northeast Kansas, May 1994 through May 

1995: U.S. Geological Survey Water-Resources Investigations Report 97-4019, 66 p.

Thornton, K.W., Kimmel, B.L., and Payne, F.E., eds., 1990, 

Reservoir limnology ecological perspectives: New 

York, John Wiley & Sons, 246 p.

Welch, E.B., and Cooke, G.D., 1995, Internal phosphorus 

loading in shallow lakes importance and control: 

Lake and Reservoir Management, v. 11, no. 3, 

p. 273-281.

Wetzel, R.G., 1983, Limnology (2d ed.): New York, Saunders College Publishing, 767 p.

24 Analysis of Bottom Sediment to Estimate Nonpoint-Source Phosphorus Loads for 1981-96 in Hiiisdaie Lake, Northeast Kansas
SUPPLEMENTAL INFORMATION

Supplemental Information 25
26 Analysis of Bottom Sediment to Estimate Nonpoint-Source Phosphorus Loads for 1981-96 in Hillsdale Lake, Northeast Kansas
Table 13. Latitude and longitude coordinates for the end points of the U.S. Army 

Corps of Engineers range lines used in bathymetric surveys of Hillsdale Lake1

Range line

(fig. 2)

1

2

3

4

5

6

7

8

9

10

12

13

14

15

16

18

End

latitude 

(decimal 

degrees)

38.6473

38.6473

38.6589

38.6675

38.6801

38.6930

38.7049

38.6996

38.7081

38.7246

38.6412

38.6807

38.6847

38.7040

38.7198

38.6613

point A

longitude 

(decimal 

degrees)

94.9158

94.9158

94.9248

94.9283

94.9467

94.9606

94.9740

94.9992

94.9764

94.9696

94.9368

94.9185

94.9076

94.8896

94.8720

94.9454

End point B

latitude 

(decimal 

degrees)

38.6625

38.6582

38.6675

38.6806

38.6895

38.7001

38.7081

38.7015

38.7082

38.7238

38.6491

38.6734

38.6813

38.7024

38.7191

38.6671

longitude 

(decimal 

degrees)

94.8982

94.9219

94.9283

94.9187

94.9336

94.9511

94.9764

95.0002

94.9591

94.9607

94.9367

94.9056

94.8971

94.8789

94.8661

94.9453

Range lines 11 and 17 were not used in the study. Respectively, the range lines are located upstream from 

Hillsdale Lake on the Big Bull Creek and Little Bull Creek channels. Because neither range line was considered 

necessary for estimating total sediment deposition in the lake, they were not surveyed by the U.S. Army Corps 

of Engineers or the U.S. Geological Survey in 1996.

Supplemental Information 27
9L

I 

0> 

o

DO 

Q

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I

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|

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i

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0

o

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Southwest 

945

940

935

930

925

- 920

915

910

905

900

895

890

885

1978 U.S. Army Corps of Engineers topographic data

1993 U.S. Army Corps of Engineers bathymetric data 

1996 U.S. Army Corps of Engineers bathymetric data

1996 U.S. Geological Survey bathymetric data

500 1,000 1,500 2,000 2,500 

Distance along range line 6, in feet

3,000 

Figure 8. Comparison of 1996 U.S. Geological Survey bathymetric data, 1978 U.S. Army Corps of Engineers topograph

Army Corps of Engineers bathymetric data for Hillsdale Lake range line 6. Location of range line shown in figure 2.
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Supplemental Information 29
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915

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1978 U.S. Army Corps of Engineers topographic data

1993 U.S. Army Corps of Engineers bathymetric data (channel only)

1996 U.S. Army Corps of Engineers bathymetric data

1996 U.S. Geological Survey bathymetric data

i i i i i i i i i

500 1,000 1,500 2,000 2,500 3,000 3,500 4,000 4,500 

Distance along range line 4, in feet

Figure 10. Comparison of 1996 U.S. Geological Survey bathymetric data, 1978 U.S. Army Corps of Engineers topographic dat

Corps of Engineers bathymetric data for Hillsdale Lake range line 4. Location of range line shown in figure 2.
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Supplemental Information 31
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925

920

915

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905

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880

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1978 U.S. Army Corps of Engineers topographic data

 1993 U.S. Army Corps of Engineers bathymetric data 

1996 U.S. Army Corps of Engineers bathymetric data 

1996 U.S. Geological Survey bathymetric data

Borrow area during 

construction of 

Hillsdale Dam

500 1,000 1,500 2,000 2,500 3,000

Distance along range line 13, in feet

3,500 4

Figure 12. Comparison of 1996 U.S. Geological Survey bathymetric data, 1978 U.S. Army Corps of Engineers topographic dat

Corps of Engineers bathymetric data for Hillsdale Lake range line 13. Location of range line shown in figure 2.
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Supplemental Information 33
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Supplemental Information 35
9C s|sA|euv jo uiouog luauijpas 01 ajeuiusg aojnos-nnoduoN soioijdsoijd speoi JOj 96-1-861 u| aiepsmH '«vn iseaijiJON sesuex 

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range- (bathymetric 

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Supplemental Information 39
I 

1

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m

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i

i

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|

o 

v>

w

o

South 

944

942

940

938

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932

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c

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918 

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914 

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908

1978 U.S. Army Corps of Engineers t

1996 U.S. Army Corps of Engineers b

0 200 400 600 800 1,000 1,200 1,400 1,600 1,800 2,000

Distance along range line 12, in feet

2,200 

Figure 20. Comparison of 1978 U.S. Army Corps of Engineers topographic data and 1996 U.S. Army Corps of Engineers ba

range line 12. Location of range line shown in figure 2.
Q.

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Supplemental Information 41
IO

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1978 U.S. Army Corps of Engineers topographic data 

1996 U.S. Army Corps of Engineers bathymetric data

200 400 600 800 1,000 1,200 

Distance along range line 16, in feet

1,4

Figure 22. Comparison of 1978 U.S. Army Corps of Engineers topographic data and 1996 U.S. Army Corps of Engineers ba

range line 16. Location of range line shown in figure 2.
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Supplemental Information 43
95°01' 

38°45'i 

59' 57' 55' 53' 940 51'

43'

41'

38°39'

Hilisdale

Lake \26

Hilisdale 

Dam

Base from U.S. Geological Survey digital data, 1:24,000,1973

Lambert Conformal Conic projection

Standard parallels 33° and 45°, central meridian 98°15'

3 MILES

2 3 KILOMETERS

EXPLANATION

:1::||||| Extent of Hilisdale Lake at conservation-pool 

elevation (917 feet above sea level)

^ Bathymetric range line and numbei Established by 

U.S. Army Corps of Engineers

10 

_ _ _ _ Bathymetric range line and numbei Established by

U.S. Geological Survey

Figure 24. Additional bathymetric survey lines completed by the U.S. Geological Survey at Hilisdale Lake in 1996.

44 Analysis of Bottom Sediment to Estimate Nonpoint-Source Phosphorus Loads for 1981-96 in Hilisdale Lake, Northeast Kansas
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Supplemental Information 45
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500 1,000 1,500 2,000 2,500 3,000 3,500

Distance along range line 20, in feet

4,000 

Figure 26. 1996 U.S. Geological Survey bathymetric data for Hillsdale Lake range line 20. Location of range line shown in figure 
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Supplemental Information 47
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Distance along range line 22, in feet

5 Figure 28. 1996 U.S. Geological Survey bathymetric data for Hillsdale Lake range line 22. Location of range line shown in figur
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Figure 30. 1996 U.S. Geological Survey bathymetric data for Hillsdaie Lake range line 24. Location of range line shown in figure 
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Figure 34. 1996 U.S. Geological Survey bathymetric data for Hillsdale Lake range line 28. Location of range line shown in f
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Figure 35. Relation of sediment bulk density to percent moisture content for 19 sediment-core samples 

from Hillsdale Lake.

GOVERNMENT PRINTING OFFICE: 1997-656-309 Supplemental Information 55